Gut microbiota has become an integral component of the host, and exerts on host biology. Due to its importance, host intestinal bacterial community has received more and more attention. However, for domestic animal, learning about the intestinal bacterial community is insufficient. Efforts also should be paid to manage gastrointestinal microbiota. Understanding factors that influence the composition of microbial community of the alimentary canal of host will be key in regulating the microflora. We performed 16S rRNA gene sequence-based comparisons of bacterial communities in fish intestinal content and fish culture-associated environments including diet.